[AA] Pass AAResults through AAQueryInfo

Currently, AAResultBase (from which alias analysis providers inherit)
stores a reference back to the AAResults aggregation it is part of,
so it can perform recursive alias analysis queries via
getBestAAResults().

This patch removes the back-reference from AAResultBase to AAResults,
and instead passes the used aggregation through the AAQueryInfo.
This can be used to perform recursive AA queries using the full
aggregation.

Differential Revision: https://reviews.llvm.org/D94363